South Africa to Build Largest Telescope South of the Equator

8 July 1998
Africa News Service (Durham)

Washington, DC — The South African Cabinet has approved the construction of the Southern Hemisphere's largest and most advanced telescope.

To be located at the existing site of the South African Astronomical Observatory (SAAO), on the Karoo plateau to the north-east of Cape Town, the South African Large Telescope (SALT) will use a revolutionary multi- mirror design to provide state-of-the-art observing power at a promised fraction of the cost of conventional single-mirror telescopes.

"Africa will get a giant eye to the universe," proclaimed Dr. Khotso Mokhele, President of South Africa's Foundation for Research Development, in an official statement reacting to the government's decision.

The approval of SALT will give a major boost to South African astronomy's long-established tradition of world-class research. The first continuously operating observatory sited on African soil was set up by the British Admiralty at Cape Town in 1820 to provide accurate charts of the southern skies. More recently, South African-based astronomers were the first to measure the distance to another star, pioneered efforts to determine the distance of the Earth from the Sun, and were the first to detect crucial elements outside our solar system such as oxygen and silicon.

Once built, SALT will be the southern sister to a similar facility, the Hobby-Eberly Telescope (HET) that recently went into operation at the McDonald Observatory in Texas. Fifty percent of the telescope will be built domestically in cooperation with the HET's Texas-based engineering team. The government hopes that South African industry will benefit from the project's technology spin-offs in such fields as robotic machine tools.

The HET design breaks an impasse in the development of ground-based optical telescopes. Older telescopes, including the world's largest, use a single parabolic reflecting dish to collect light. Built of massive glass discs, the surface of mirrors larger than about six meters in diameter gradually becomes distorted, as the glass slowly flows under its own weight.

Instead of a single mirror, SALT will use 91 easily manufactured one- metre mirrors in a hexagonal array 11 metres across. In a further cost- saving departure from conventional telescopes, the mirrors remain in a fixed position, with only a set of tracking optics at the top of the telescope following the object under observation as it moves across the sky. The design allows nine meters of mirror diameter to be brought to bear at any one time, yielding 23 times the light-gathering capacity of Africa's largest existing telescope -- SAAO's 1.9 metre instrument.

In astronomy, size does matter. More light collection gives SAAO's researchers the ability to study objects one hundred times fainter and ten times more distant than they could previously. This is not just a matter of scientific perfectionism: ten times further means ten times older, allowing SALT to probe the nature of the universe shortly after the "Big Bang" by gathering data on quasars and infant galaxies.

Closer to home, SALT promises new insights into the nature of our own galaxy -- at South Africa's latitude the centre of the Milky Way passes directly overhead -- and will aid in the search for planets orbiting other stars.

SAAO's director, Bob Stobie says, "The main argument for having a really large telescope in South Africa is the unique geographical situation. We're south of the equator in a unique longitude range. There's really no other observatory for thousands of kilometres round about. So we can make unique observations?"

Clearly, the government's decision is exciting news, not just for South African star watchers but also for world astronomy. Cost effective as SALT will be, however, it is not in absolute terms, cheap, carrying as it does a five-year price tag of R100 million ($20 million). Planners hope that, in return for observation time, foreign collaborators will provide half the funds, but this still leaves a substantial slice to come out of the South African government's regular budget for science and technology.

The building of a state-of-the-art research facility in South Africa for what is perhaps the purest of the pure sciences has raised in an acute form a more down-to-earth concern: Can a nation for the first time attempting to distribute its resources in the interests of the majority of its population justify this type of project?

The achievements of South African astronomy, like the rest of the country's "first world science on third world soil," were ultimately made possible by a social system run by and for the white minority. Senior SAAO astronomer Patricia Whitelock, a specialist in infrared astronomy and head of the observatory's educational outreach program says, "Science let people down during the apartheid era. Perhaps scientists let people down to some extent. ' Underprivileged communities were basically excluded from doing any science or mathematics in the apartheid era."

Against the background of a country where many schools lack not only the most basic technical facilities for teaching science but even electricity, SAAO's astronomers must argue hard if their work is not to be seen as no more than a form of elite self indulgence. The government's decision to back SALT is due in no small part to the vigor with which the scientists have made their case.

Stobie says that SALT can make a vital contribution to the national self-image. "Clearly whether astronomy exists or not in South Africa is not going to make a difference right away to people's daily lives, " he says. "But you've got to recognize that astronomy is working at the frontiers of technology, so it would give South Africans something to look up to in terms of pride.

"Furthermore I think it will have a very major impact on the youth of the country; it could encourage more people to take up careers in science and technology, which the country badly needs."

Science, he believes, can provide South Africans with an alternative source of pride to their post-apartheid sporting achievements: "People look up to the [1997 world champion] Springboks as being a great rugby team. Why can they not look up to a scientific facility that's right at the leading edge?"

One concrete step SAAO has taken to stimulate the kind of popular scientific awareness that Stobie calls for has been its establishment of an educational outreach program. Set up in 1994, the program has developed materials for teaching science at school level, and guides teachers in putting them to work in the classroom.

For Whitelock, the initiative is an attempt to take on the debilitating after-effects of apartheid for scientific education. "There's a dire problem in this country with science. ' Lots of schools don't have science teachers at all, particularly the black schools, and those that do have science teachers that are not properly qualified'

"There's really a lot of work to do to bring those schools up to scratch and particularly to provide them with capable science teachers. So one of the things we're trying to do is to show teachers how they can make science look exciting."

She feels that astronomy has a particular role to play in sparking this enthusiasm, "People perceive science as being both dull and difficult and astronomy is anything but dull. ' There are lots of things you can do and learn in astronomy which are actually quite easy to understand, and you realize at the end of it that you understand something which is really quite impressive and quite exciting."

Although well aware of the shortcomings of apartheid-era science, Whitelock is eager to combat any emerging tendency to treat science itself as inherently hostile to the needs of black Africans. "Science is very neutral, it's a tool," she insists.

"It's also rather frightening that in order to get away from the West there's talk of things like 'African science.' The science that we have today -- in many ways it was born out of the Western tradition, but the East has made vast contributions to it. I think that the Indians and the Chinese and the Japanese would be somewhat distressed to hear it referred to as 'Western science.'"

Despite her awareness of the problems SA faces in democratizing science, Whitehead is hopeful for the future. She sees, "an incredible potential in the people and the resources ' if it can be built on, I think we can achieve great things."

Official statements suggest that the post-apartheid authorities agree with the astronomers of SAAO that South Africa needs high-profile scientific projects like SALT. According to a recent government White Paper, or policy document, "Not to offer 'flagship' sciences such as physics and astronomy would be to take a negative view of our future -- the view that we are a second class nation, chained forever to the treadmill of feeding and clothing ourselves."

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